The situation่, in which the graft rejects the host’s tissues, is
called the graft-versus-host reaction (GvHR), this occurs when the
immunocompentent cells are transferred into the
immunoincompenet recipient(the host). There are 3 conditions for
GvHR: 1. histoincompatibility between the donor
andrecipient(host), 2. adoptive transfer of immunocompetent cells
(particularly T cells), and 3. immunodeficiency of the recipient.
This lead to the attack of the graft on the host’s tissues; it leads to
graft-versus-host disease (GvHD). The resulting GvHD can be acute
or chronic. Acute GvHD is a progressive, systemic disease
characterized by epithelial cell necrosis, mainly in the
gastrointestinal tract, liver, and skin. Chronic GvHD is a pleiotropic
syndrome characterized by fibrosis and atrophy of the same
organs, but with no sign of epithelial cell necrosis.